GWh

Gigawatt-hour (GWh) is a unit of energy used in electricity markets, resource planning, and energy statistics. It represents the amount of energy equivalent to one billion watt-hours. Since one watt-hour is 3,600 joules, one gigawatt-hour equals 3.6 × 10^12 joules. It also equals 1,000 megawatt-hours (MWh) and 0.001 terawatt-hours (TWh).

GWh measures energy over a period, not power at an instant. For example, a generator with a capacity of 1 gigawatt that runs at full output for one hour produces 1 GWh; the same plant running for 24 hours yields 24 GWh.

Applications include reporting annual grid generation, regional energy demand, and contract quantities in electricity markets. It is common to compare GWh with other energy units such as TWh (1,000 GWh) and MWh (1,000 MWh).

Notes: GWh is often used for large-scale energy planning and to express production and consumption over time, as opposed to power ratings like GW, which describe capacity at a moment. The unit is additive over time and can be used to aggregate diverse generation sources, though losses and efficiency affect actual delivered energy.